Toast the sesame seeds: Preheat your oven to 350°F (175°C). Spread the raw sesame seeds on a baking sheet in a single layer and toast for 5-7 minutes, or until they're fragrant and slightly browned. Stir the seeds occasionally to ensure even toasting.

Cool and grind the sesame seeds: Remove the toasted sesame seeds from the oven and let them cool slightly. Then, use a coffee grinder or food processor to grind the seeds into a fine powder. This may take a few minutes and several rounds of grinding.

Mix the ground sesame seeds with salt and lemon juice: In a mixing bowl, combine the ground sesame seeds, salt (if using), and lemon juice. Mix well until the ingredients are thoroughly combined.

Add water and continue mixing: Slowly add the water to the sesame seed mixture, stirring constantly. Continue mixing until the mixture becomes smooth and creamy. You may need to scrape down the sides of the bowl occasionally to ensure everything is well combined.

Strain the tahini extract: Place a cheesecloth or fine-mesh strainer over a glass jar and pour the sesame seed mixture into the strainer. Allow the mixture to strain for several hours, or overnight, to remove any remaining solids and create a smooth, velvety tahini extract.